Somehow, Mikeneko of all people has a subgroup of fans that hate her parasocial unicorns and had been stirring shit up trying to pressure her into doing male collabs to own them. The person who posted the original tweet here is part of that group. She is a Taiwanese feminist and one of Mike's biggest fan artists.
What you're witnessing is the aftermath of Mikeneko telling them to knock that shit off and them not being able to let it go after their side seemingly lost. The post by Quix is accurate enough. In her last twitcast she said she loves her unicorns, she wouldn't do male collaborations, and the people bitching about it need to stop.
It's pretty much just a tantrum for not getting their way, while actively ignoring or lying about what Mike said. It's hypocritical to the extreme, because people in her circle have been painting her unicorns as not obeying her wishes and doing things that hurt her, and then immediately started sulking and doing shit like this against her wishes after she told them off.